Field-discharge switch



W. M. AUSTIN FIELD DISCHARGE SWITCH Dec. 28 1926.

2 Sheets-Shet Filed Mav 19. 1923 TTORNEY W. M. AUSTIN FIELD DISCHARGE SWITCH Deep. 28 1926.

Filed Mav 19. 1923 2 Sheets-Sheet 2 @l f g fz mw 63% INVENTOR lA/a/zex" /"7. A us 27 ATTORNEY Patented Dec. 28, 1926.

VJ'AL'IER M. AUSTIN, OF SWISSVAJLE, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING VANIA.

CGMPANY, A CGRPORATION GF PENNSYIr FIELD-DISCHARGE $WITCEI.

Application filed May 19,

My invention relates to circuit interrupters and particularly to field discharge switches associated therewith.

One object of my invention is to provide a field discharge switch for circuit interrupters, that operates to minimize the inductive surge encountered upon interrupting a circuit having a highly inductive load.

Another object of my invention is to pro vide a field discharge switch for circuit interrupter, the operation of which is governed by the movement of the circuit interrupter.

Another object of my invention is to provide interlocking means between a field discharge switch and a circuit interrupter for preventing the movement of the field discharge switch while the circuit interrupter is in its fully open or its fully closed positions.

A further object of. my invention is to provide a field discharge switch for circuit interrrupters, that closes and opens in advance of the opening and closing of the circuit interrupter, respectively.

A. still further object of my invention is to provide a field discharge switch, for circuit intcrrupters having means for mechanically interlocking a movable member of the discharge switch with a movable member of the circuit interrupter, whereby a positive operation of the discharge switch will be obtained in sequence with the operation of the circuit interrupter.

It is a well known fact that when an electrical circuit having a highly inductive load is suddenly interrupted, the excessive reaction, or inductive surge, in the circuit tends to impair the insulation thereof and generates excessive arcing at the point of interruption.

My invention comprises a field discharge switch having a stationary contact member and a pivoted blade member adapted for engagement therewith, which is mechanically interlocked with a circuit interrupter of the usual type having a movable bridging member co-operating with a plurality of stationary contact members. The field discharge switch operates in sequence with the circuit interrupter, as it closes and opens just prior to the opening and closing of the circult interrupter, respectively. The switch is actuated through a pawl and ratchet struc- 1923. Serial No. 640.641.

ture during movement of the circuit interrupter, as will be hereinafter specifically set forth.

e, I. have shown the preferred form of my invention,-

in which Figure 1. is a side view in elevation of a field discharge switch and a circuit interrupter embodying my invention.

Fig. 2 is a front view in elevation of the device shown in Fig. 1.

Fig. 3 is a View similar to Fig. l, illustrating the position of the discharge switch blade when the circuit interru iiter is in the circuit interrupting position.

Fig. 4 is a View similar to Fig. l, illus trating the position of the discharge switch blade when the circuit interrupter is in the circuit closing position.

Fig. 5 is a view illustrating, diagrammatically, the application of my invention to a circuit comprising a field wiluliug for an electrical device.

In the preferred form of my invention a field discharge switch '1 is interlocked with a circuit interrupter 2 by a rod 3. The field discharge switch 1 comprises a stationary contact member 4, a hinge jaw member 5 and a pivoted blade member 6 supported by a jaw member 5 and adapted to engage the contact member 4.

The hinge jaw 5 also pivotally supports at either side of the switch blade 6 a stirrup 7 of substantially U-shape. The stirrup 7 pivotally supports a plurality of pawl members 8 and 9 by a pin 10. The pawl members 8 and 9 are adapted to engage a ratchet 11. which is rigidly mounted on the switch blade 6. The outer edge of the ratchet 11 is provided with teeth 12 and 12a. and 13 and 13a, the respective pairs of teeth coacting with pawls 8 and 9. A spring 14 that is disposed between the pawls 8 and 9 yieldingly maintains them in engagement with the ratchet 11.

Link members 15 are pivotally secured at one end to the stirrup 7 by the pin 10, and at their other ends by mounting 16 on the interlocking rod 3. These links cause the stirrup 7 to be actuated about the operative face of the ratchet 11 when the handle of the interrupter 2 is moved from one position to another.

The hinge jaw 5 supports also a cam member 17 that is parallel to the ratchet 11 and is provided-with two extended portions 18 and 19 which lie in the path or tr rel of the pawls 8 and 9, for the purpose of lifting the pawls out'ot' engag" the teeth 12 and 13 of the latch will be hereinafter described.

A stop member 20 is disposed between the jaws of the stationary contact member l to limit the movement or the blade 6 when it engages the contact member 1. A second stop member 21 is disposedat the base of the cam member 17 to limit the movement of the blade 6 when it is disengaged i'rom the contact member 4.

The circuit interrupter 2, for which the field discharge switch 1 is adapted, may be of any general type comprising a plurality of stationary contact members 22 and 28, a movable bridging member 24 adaptedii or engagement therewith, a plurality of auxiliary contact members25 and 26,. and;an operating handle 27. The contact members 26 maybe of the carbon block type. The details of the circuit interrupter form no part of my present invention.

' The movement or the blade 6 of the field discharge switchl is dependent upon the operation of the circuit interrupter 2. 'When the handle 27 of the circuit interrupter 2 is inits lower position, the bridging member 24 engages the stationary contact members 22 and23, the auxiliary contact members 25 and 26 are also in engagement, and the blade'6 of the field-discharge switch 1 is disengaged from the stationary contact member 4, as shown in'Fig. 1.

lVhen the circuit interrupter 2 is opened, the handle. 27 is raised, upwardly and by means ofthe interlocking rod'3 and links 15, the stirrup 7' is also actuated upwardly. The pawl 8 engages the tooth '12 of the. ratchet 11, thereby actuating the switch blade 6 of et 11, as

the field discharge switch 1, whichenga 'e.

the stationary contact member 4:. The blade (5 engages the contact'member/l. just. prior to the separation, of the auxiliary contact members 25 and 26 of the circuit interrupter, as is shown in Fig. 3. Shortly after the blade 6 engages .the contact. 4, the pawl 8 engages the projection '18 of the .cam 17 and is raisedtrom the notch 12 of the .ratchet ll, and; brought into engagement with the tooth 12a for the purpose locl mg the'dlscha'rge SWltCll' 1 1n the closed position while the circuit interrupter-'2 is in the open position.

Upon closing the circuit interrupter 2, the handle 27 is moved downwardly and the pawl'9 engages in tooth 13 otthe ratchet 11, causing the blade :6 of the discharge switch 1 to be disengaged from the contact member l just "or to the closing oithe carbon conta s or the circuit interrupter. The pawl 9 will now engage the projection 19 ment. with cuitof an electric motor 28.

o1 the cam 17 and is lifted into engagement 5 th the tooth 13c oi? the ratchet 11 for the purpose of locking the discharge switch 1 in the open position while the circuit interrupter 2 is in the closed )osition.

Reference may be hat to: Fig. 5 .in'which l have illustrated, diagrai'nmatically, the application of my invention'to the field cir- Upon interruption of the circuit supplying the motor 28 by manipulation of the circuit interrupter 2, the lielddischarge switch 1, closes, thereby completing a circuitcomprising the'field winding 29 and a resistor 31. The inductive surge set up by. the stored energy. in A coil 29 is, accordingly, dissipated in resistor 31 rather than dissipated in the form oi": are energy between the rela 'zively movable contact members of the circuit interrupter'2.

It will thus be seen that" I have provided a circuit interrupter in combination with a iield discharge switch, of such design that the inductive surges incidential to the interruption of the main circuit ofan inductive electrical device are dissipated in a resistor controlled by an auxiliary switch, rather than dissipated in the form of. are energy between the relatively movable contact member-sot the circuit interrupter.

Various modificationsmay be made in my invention without departing fromithe spirit and scope thereof, as set forth, inthe appended claims.

I claim as my invention:

1. The combination with a circuitinterrupter comprising a movablemember, of a switch comprisinga movableblade member, latching'means for preventingthe opening of said switch while the circuit interrupter is in its maximum open. positionandfor preventing the closing. of said" switch-while the circuit interrupter is inrits'completely closed position.

2. The combination with a manually operated circuit interrupter having an operating handle thereon, of a switch comprising. a pivoted blade-member, a co-operating contact member, a ratchet integral with; said blade member, a plurality of pawl members (to-operating with said ratchet, pawlsupporting means pivotally carried"by said blade member, and a link mechanism connecting said pawl supporting meanswith the operating handle of said circuit interrupter.

3. The combination with a circuit interrupter comprising an operating handle,.of a switch comprising a contact member, a hinge member, a knife blade member pivotally supported by said hinge. member and adapted to engage said contact member, a ratchet carried by said blade, a plurality of pawl members adapted to engage said ratchet, a stirrup of substantially cl-shape pivotall supporting said pawl members, and

lie

a plurality of link members supported at one end by said stirrup and, at the other end, by a pivotal connection to the operating handle of said circuit interrupter.

4. The combination with a circuit interrupter comprising an operating handle, of a switch comprising a stationary contact member and. a knife blade member adapted to co-operate therewith, a ratchet rigidly supported by said blade, a plurality of pawl members adapted to engage the surface of said ratchet, a stirrup pivotally supporting said pawl members, a cam member for engaging the pawl members to effect the disengagement of said pawls from said ratchet, means comprising said pawls for locking said blade member in closed or open position when the circuit interrupter is in open or closed position, means for limiting the opening and closing movement of the blade, and a plurality of link members for connecting said stirrup to the operating handle of said circuit interrupter.

In testimony whereof, I have hereunto subscribed my name this 14th day of April, 1923.

WALTER M. AUSTIN. 

